Systems and methods herein generally relate to conveyor systems that move sheets, and more particularly to apparatuses that determine the sheet height of a sheet on a conveyor.
As the quality and speed of printing devices improve, the tolerances within such printing devices decrease. These tighter tolerances can cause problems if the print media being utilized has an inconsistent thickness. Specifically, if a sheet of print media is thicker than the tolerances within the printing device, the print media can jam within the printing device and/or damage the internals of the printing device. Therefore, systems that can determine the height of the print media accurately are highly valued.
For example, in a direct marking ink jet printer, the print heads are at risk of damage if struck by media on which the print heads are jetting. Typically print heads are within 1 mm from the media. Cut sheet printers add a degree of difficulty over a web fed printer because cut sheets are more difficult to constrain. Furthermore, cut sheets are prone to cockle and curl. There it is useful to measure the sheet height above the paper path in order to inform the system that a potentially hazardous sheet is about to enter the print zone.